Work engaging support for a rock drill



March 24, 1959 o. M cowAN WORK ENGAGING SUPPORT FOR A ROCK DRILL Original Filed Dec. 6, 1954 2 Sheets-Sheet 1 a 12704922202.- (900212 212 fowan imW March 24, 1959 on M. cowAN WORK ENGAGING SUPPORT FOR A Rocx DRILL 2 Sheets-Sheet 2 Original Filed Dec. 6, 1954 I 10w 19am 2:! a2 fail/n22. 0221222655 \m n a u QN 4. G 4. J: an a a. 4. I ...v r z IF. IL I mll I 1.! lll m Q Q WORK ENGAGING SUPPORT FOR A ROCK DRILL of the drilling implement.

United States Patent David M. Cowan, Columbus, Ohio, assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Original application December 6, 1954, Serial No. 473,207. Divided and this application August 18, 1955, Serial No. 529,121

4 Claims. (Cl. 255--45) parted thereto powerful rotating forces, in order to speed up the drilling process, particularly in relatively hard rock, and it has been found that in such drills the guide frame along which the drilling tool is guided must be held steady in order that a straight and true hole may beassured. While various known attempts have been made to maintain the drilling implement along a straight and true course the results have not been entirely satisfactory in a relatively powerful, high pressure drill and, in known instances, when tremendous pressures are involved, previous devices have been found not to be entirely satisfactory. The present invention contemplates improvements over such known drills in that the drilling implement is firmly supported and guided with respect to the work during the drilling operation.

An object of the present invention is to provide improved guiding and steadying means for the drilling implement of a high pressure rock drill whereby the drilling implement is held steady and guided along a straight and true path duringthe drilling operation. Another object is to provide an improved work engaging member for holding the drill guide frame steady during the drilling operation. A further object is to provide improved power operated adjusting means for the drill guide frame for constantly urging the latter against the work during 7 drilling thereby to minimize vibrations and substantially is to provide a multi-pointed stinger bar at the front a end of the drill guide frame for engaging the working face at a multiplicity of points close to the periphery A still further object is to provide a tubular stinger bar secured to the front end of the drill guide frame and closely surrounding 'the drilling implement and having a multiplicity of faceengaging points contacting the working face at mini-1 mum radii from the center of the drilling implement, with the points lying in a circle concentric with the drilling implement and spaced equally apart about the circle. Still another object is to provide an improved power operated mechanism for constantly urging the face engaging member against the work during the drilling operation and having speed-multiplying means interposed between the power-actuated element and the member which engages the face whereby a powerful holding action is attained. These and other objects and advan tages of the invention will, however, hereinafter more fully appear.

2,879,034 I Patented Mar. 24, 1959 This application is a division of my copending application Serial No. 473,207, filed December 6, 1954.

In the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In these drawings:

Fig. 1 is a top plan view of .a high pressure rock drill constructed in accordance with a preferred illustrative embodiment of the invention.

Fig. 2 is a side elevational view of the rock drill shown in Fig. 1.

Fig. 3 is an enlarged perspective view of the forward portion of the drill, showing the multi-pointed stinger bar with the drill bit retracted therein.

Fig. 4 is a perspective View similar to Fig. 3 showing the stinger bar with the drill bit in partially advanced position.

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Fig. 5 is a cross section taken through the stinger bar shown in Figs. 3 and 4.

Figs. 6 and 6a, taken together, constitute an enlarged central vertical sectional view taken on line 6-6 of Fig. 1.

The improved high pressure rock drill, as shown in the drawings, generally comprises a support 1 along which an elongated drill gui-deframe 2 is guided for rectilinear endwise back and forth movements and carried at the front end of the guide frame is a work-engaging member 3 desirably in the form of a multi-pointed or serrated-faced stinger bar engageable with the face of the work, in the manner shown in Figs. 1 and 2. This stinger bar is constantly urged against the work during the drilling operation by a power feeding. or adjusting device, generally designated 4, for moving the guide frame forwardly along the support-guideways during drilling and this stinger bar serves to steady the guide frame thereby to minimize the setting up of vibrations as the drill operates. Guided for back and forth rectilinear movements along the guideways of the guide frame 2 is a rotating means, generally designated 5, for rotating a drilling implement or tool 6, the latter desirably in the form of a conventional hollow. rotary drill steel carrying a rotary drill bit 7 of the type known as a tungsten carbide bit.

In this illustrative construction, the support 1 may be adjustably mounted in various manners and is herein for illustrative purposes shown as supported by a swingable drill boom 8 (Fig. 2) on which a support 9 is swivelly mounted and carried by this support is a frame 10 turnable about an axis at right angles to the swivel axis of the support 9. Conventional motors 11 and 12 respectively serve to effect turning of the support 10 about the swivel axes. By proper adjustment of the drill boom, the swiveled support and frame, and the tiltable guide frame support 1, the drilling tool may be adjusted into and held invarious drilling positions with respect to the face of the work. Since this adjustable supporting structure is fully disclosed in my copending application Serial No. 473,207 above referred to and does not per se enter into the present invention other than its manner of cooperation therewith further description thereof is herein unnecessary.

Due to the use of heavier or more powerful forces for rock drilling in a high pressure drill of the character disclosed, a much stronger and heavier construction is demanded than is normally used for rotary drilling in softer materials, and to provide such stronger and heavier construction the guide frame support, the guide frame,

and the tool rotating means are made relatively rugged. and heavy and the moving parts are totally enclosed. within a metal housing 14 thereby to reduce access of dust and dirt encountered in drilling to the various guides and mechanisms of the drill feed, and this housing is provided with properly formed metal covers which also add materially to the strength and stiffness of the structure.

Asv shownparticular-ly inFigs. 6 and 6a, thedrill rotating means embodies a casing'15 in which a terminal driven shaft 16.;is suitably journaled, this shaft arranged with its axis of rotation extending longitudinally of the drill. This shaft has a threaded forward portion 17 to which the drill steel 6 is coupled, as by a coupling member 18. A parallel tubular shaft 19, likewise suitably journaled within the casing, has a spur gear 24) secured thereto which meshes with and drives a spur gear 21 fixedto the shaft, 16. Suitably mounted at the rear end of the guide frame 2 is a transmission housing 23 and carried at the rearward portion of this housing is a motor 2 4, de'sirably a conventional hydraulic motor, and this housing contains a conventional selective two-speed transmission or reduction gearing 25 (Fig. 6) for connecting the motor 24 to an elongated splined drive shaft 26 extending longitudinally of the drill guide frame 2 and suitably journaled on the latter in front and rear bearings 27 and 27. The tubular shaft 19 surrounds the shaft 26 and carries conventional splines engaging the splineways of the shaft 26 so that this shaft may drive the intermeshing gearing 20, 21 as the drill rotating means 5 moves rectilinearly along the frame guideways.

Mounted at the forward end of the guide frame is a bracket or supporting frame 28 and the face-engaging member or stinger bar 3 is rigidly secured to this bracket. This stinger bar is desirably of tubular sleevelike form, as shown at 29, and closely surrounds the drill steel, as shown most clearly in Figs. 3 and 4. This sleevelike member has a rear flange 30 having openings through which screws 31 extend into threaded connection with a front tubular portion 32 of the bracket 28. The tubular portion 32 carries a bearing 33 in which the drill steel 6 is journaled. The sleevelike member 29' has its walls cut away, as by slots 34, to permit ready access to the screw heads (Figs. 4 and 5) and any dirt which may enter the sleeve member may be discharged laterally through these openings.

The rigid, sleevelike stinger bar 29 has a multiplicity of, herein desirably four, equally spaced points or toothlike serrations 35 arranged at minimum radii from the center line of the drill steel and these closely spaced points or teeth maybear firmly against the working face so that the preloading of the stinger bar is concentric with the thrust load on the drill bit. The stinger bar thus reduces any tendencyof relative bending motion between the drill steel and the stinger bar as the thrust load is applied to the drill bit. Thus, the guide frame and drill steel may be held steady during axial feeding of the bit.

The power operated means 4 for urging the guide frameforwardly to maintain the stinger bar firmly against the work during drilling comprises a hydraulic motor having a hydraulic cylinder 37 (Fig. 6) secured to and arranged longitudinally within the support 1 and this cylinder contains a reciprocable piston 38 having its piston rod 39 extending forwardly from the front end'of the cylinder. This piston rod is threadedly secured at its forward end of a shaft mounting or bracket 40 on the shaft of which a spur pinion 41 is journaled for free rotation. This spur pinion meshes with the teeth of opposed parallel racks 42 and 43 respectively secured to the support 1 and the sliding frame 2. Thus, when liquid under pressure is properly supplied to the cylinder 37, the piston is moved within the cylinder to cause the pinion and racks to effect movement of the sliding frame 2 at a speed twice as fast asthe rate of travel of the piston 38- thereby to move the stinger bar against the work. A constant leak of liquid under pressure to the rear end of the cylinder causes the piston constantly to urge the stinger bar firmly against the work during the drilling operation.

Now referring to the feeding means for the drill rotating means 5 for moving the latter rectilinearly back and forth along the guideways. of the guide frame 2, it will be noted that a motor 45, desirably a conventional reversible hydraulic motor, is mounted on the forward portion of the transmission housing 23 (Fig. 6), and the motor power shaft is coupled, at 46, to a horizontal shaft 47 extending longitudinally of the drill and suitably journaled within the gear housing. Secured to the shaft 47 is a worm 48 meshing with a worm wheel 49 having its hub keyed to a transverse shaft 50 suitably journaled within the housing 23. The shaft 50 is operatively connected to chain sprockets 51 which engage and drive parallel feed chains 52, as is fully described in my copending application mentioned above. These feed chains are attached, at their ends, to the sliding drill casing 15. By properly supplying liquid under pressure to the reversible, motor 54-the feed chains 52 may be driven to elfect feeding of the rotating means 5 either forwardly or rearwardly along the frame guideways.

The general mode of operation of the improved rotary drill is as follows: When the drill is properly positioned 0nv its adjustable mounting with respect to the working face, the hydraulic motor 37 may be operated to actuate the rack and pinion mechanism 41, 42, 43 to advance the sliding frame 2 rectilinearly along its guideways on the support 1 thereby to bring the stinger bar 3 against theface of the work, and this motor acts continuously during the drilling operation constantly to urge the stinger bar firmly against the working face. It may be assumed that the drill rotating means 5 is at this time inretracted position on the guide frame and the drill steel rotating motor 24 is running to rotate the drill steel at the proper selected speed under the control of the selective transmission. The feed motor 45 may then be operated to actuate the feed chains 52 to feed the drill rotating means forwardly along the frame guideways thereby to cause the drill bit to penetrate the rock or other material being drilled. During starting of the hole the stinger bar 3, firmly engaging the face close to the drill bit and the bearing 33 within the tubular portion 32 in which the drill steel is journaled, maintain the bit centered.

The drill is operated at relatively high hydraulic pressures and the force exerted by the hydraulic frameadjusting motor 37, which urges the guide frame forwardly against the working face, may be in the vicinity of 7,000 pounds while the feeding pressures exerted by the feed chains 52 actuated by the feed motor 45 may be in the vicinity of 4,000 to 6,000-pounds. The'separate drives for the rotation and feed are provided, with independent sources of liquid under pressure so that the demands of one function will not affect the other, thereby to provide greater control over rotation speeds and feed pressures for varying drilling conditions.

As a. result of this invention, an improved rotary rock drill is provided which is operated under high hydraulic pressures to effect drilling rapidly and with increased efliciency even in rock which is unusually hard. By the provision of the stinger bar which engages the working face at a multiplicity of points close to the exterior periphery of the drill steel, the drill is adequately supported and maintained steady during the drilling operation. The rack and pinion mechanism operated by the adjusting motor for the guide frame not only firmly urges the guide frame forwardly against the work but, also provides for: compactness. These and other advantages of the invention will be clearly apparent to those skilled in the art. I

Whilethere is in this application specifically described one form which the invention may assume in practice,

it will be understoodthat this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a drill of the character disclosed, a support, a guide frame guided on said support for rectilinear movement longitudinally therealong, a drill rotating means guided on said guide frame for rectilinear longitudinal movement along a parallel path, said rotating means adapted to rotate a rotary drill steel carrying a drill bit, a non-rotating tubular stinger bar rigidly secured to the front end of said guide frame against movement relative thereto and extending in advance of said guide frame, said stinger bar engageable with the face of the Work being drilled thereby to resist the powerful torsional forces transmitted to said guide frame during the drilling operation, and means for constantly urging said guide frame forwardly relative to said support during drilling for firmly holding said stinger bar against the work, said drill steel extending axially within said tubular stinger bar and the latter engaging the Working face at points close to and spaced about the drill steel.

2. A drill as set forth in claim 1 wherein said tubular stinger bar has a multiplicity of points contacting the Working face close to the steel-periphery at points spaced about the drill steel.

3. In a rotary rock drill, a longitudinally movable drill guide frame, a non-rotating tubular stinger bar rigidly secured to the front end of said guide frame against movement relative thereto and extending in advance of said guide frame, said stinger bar engaging the working face thereby to resist the powerful torsional forces transmitted to said guide frame during the drilling operation, a drill rotating means guided on said guide frame for movement therealong and adapted to rotate a rotary drilling implement, said tubular stinger bar closely surrounding said drilling implement and engaging the working 6 face close to the exterior periphery of said drilling implement, and means for constantly urging said guide frame forwardly to hold said stinger bar firmly against the work during drilling.

4. In a drill of the character disclosed, a support, a guide frame guided on said support for rectilinear movement longitudinally therealong, a drill actuating means guided on said guide frame for rectilinear longitudinal movement along a parallel path, said actuating means adapted to actuate a drilling implement, non-rotating means rigidly secured to the front end of said guide frame against movement relative thereto and extending in advance of said guide frame, said face-engaging means engageable with the face of the work being drilled thereby to resist the powerful torsional forces transmitted to said guide frame during the drilling operation, said faceengaging means comprising means providing a multiplicity of face-engaging points contacting the working face close to the exterior periphery of the drilling implement at points spaced about the implement, said points lying in a circle whose center lies at the longitudinal center of the drill and equally spaced apart along said circle, and means for moving said guide frame forwardly relative to said support for firmly positioning said facecontacting points against the Work.

References Cited in the file of this patent UNITED STATES PATENTS 1,868,373 Terry July 19, 1932 2,224,661 Suzuki Dec. 10, 1940 2,730,332 Hale Jan. 10, 1956 2,741,461 Joy Apr. 10, 1956 2,788,194 Hale Apr. 9, 1957 

